Mattress



FIG. 1 shows a perspective view of the mattress.

FIG. 2 shows a front view of the present design.

FIG. 3 shows a rear view of the present design.

FIG. 4 shows a left side view of the present design.

FIG. 5 shows a top view of the present design; and,

FIG. 6 shows a bottom view of the present design. 

CLAIM The ornamental design for a mattress, as shown and described. 